Electrical contact means for ship&#39;s compasses.



PATENTED JUNE 7, 1904.

B. FREBSB. vELECTRICAL CONTACT MEANS FOR SHIPS GOMPASSES.

APPLICATIOII FILED FEB. 21, 1903.

N0 MODEL.

Patented June 7, i904.

PATENT @EETCE.

BERNHARD FREESE, OF DELMENHORST, GERMANY.

ELECTRICAL CONTACT MEANS FOR SHIPS COMPASSES.

SPECIFICATION forming part of Letters Patent No. 762,040, dated June '7, 1904.

Application filed February 21, 1903. Serial No. 144,554. (No model.)

To all whom, it may concern:

Be it known that I, BERNHARD FREEsE, a subject of the Emperor of Germany, residing at Delmenhorst, Germany, have invented certain new and useful Improvements in Electrical Contact Means for Ships Compasses, of

which the following is a specification.

The subject-matter of this invention is represented in the accompanying drawings, in which Figure 1 is a vertical cross-section of the entire contact arrangement. Fig. 2 is a top view of the contact arrangement after removmg the card. Fig. 3 shows the lever carrying the contact-piece as seen from below.

In the base-plate a is a central mercurywell a, having a pivot Z), upon which is supported the card or face a, and surrounding the central mercury-well a are a series of contact-wells c overfilled, so as to assume con-- vex mercury contact-surfaces A above the base-plate.

' a wire to the desired place, where it is made use of in any well-known manner.

It has hitherto been difficult to apply such contact arrangement to ships compasses for the purpose of transferring the positions of the needle, owing to the fact that the directive force of the compass card or face is comparatively slight and that it is considerably affected, if not entirely neutralized, by the friction. It is therefore necessary to make use of a contact arrangement havingan extremely slight resistance to friction, and this condition is best fulfilled by adopting the well-known mercury-contact arrangement, in which the contact is effected by mercury points or heads, exceeding or projecting above the containers or receptacles, and on which the contactpiece, connected with the card or face of the compass and preferably consisting of platinum, is caused to slide; but this arrangement has, moreover, the great disadvantage that the alternate contact between the contact-pieces and the mercury heads or points causes the card or face to vibrate. Besides, vibrations of the card or face of ships compasses will necessarily be brought about by external influences and every vertical movement of the card or face renders a proper contact uncertain.

The above disadvantages are obviated by the present invention. This is effected in such manner that the contact-piece P is not fastened to the card or face direct; but it is carried by a lever H, having a contact-piece P normally in contact with the central mercury-well and jointed at P to the said card or face, the consequence being that it is free to drop in a vertical direction until it reaches the mercury points or heads /r. The leverarm 6 serves to equalize the weight resting upon said points or heads to such extent as is possible without in any way preventing a proper contact being brought about. The friction is thus reduced to a minimum and at the same time equalized, while an intimate contact between the contact-piece and the mercury points or heads isinsured. The balance of the card or face is thereby no longer affected; nor is the contact influenced by vertical vibrations. By making the arched contact-piece P equal to one and one-half divisions of the circle of heads or points of mercury it is so effected that at times it will touch two points or heads simultaneously,with the result that two circuits are closed at the same time. This may be made use of for indicating at the desired place the central position of the card or face, so that, for example, sixteen points or heads will serve to transfer thirty-two positions of the compass. This arrangement is at the same time attended with the advantage that the current used for the transfer is never interrupted, so that the formation of sparks cannot take place.

It is preferable to cover the entire arrangement with an indifferent liquid, whereby the evaporation of the mercury is prevented, and, moreover, the places or points of contact are always kept clean.

The new arrangement is particularly suitable for ships compasses,

Having thus fully described my invention, What 1 claim as new, and desire to secure by Letters Patent, is

1. In a contact arrangement on ships compasses, for electrically transferring the respective positions of the needle, the combination of a central contact and a series of contacts surrounding the central contact, a pivot, a compass card or face supported by the pivot so as not to engage the central and surrounding contacts, a lever carried by the compass card or face, and contact-pieces carried by the lever engaging the central and surrounding contacts, substantially as specified.

2. In a contact arrangement on ships compasses for electrically transferring the respective positions of the needle, the combination of a central contact, a series of contacts surrounding the central contact, a pivot, a card or face supported by the pivot so as not to engage the central and surrounding contacts,

a lever jointed to the card or face, and contact-pieces carried by the lever, one of Which normally engages the central contact continuously and the other of Which moves upon the surrounding contacts as the card or face moves upon its pivot, substantially as speci- 3. In a contact arrangement on ships compasses for electrically transferring the respective'positions of the needle, the combination of a base-plate having a central mercury-Well, a pivot centrally located in the Well, a series of surrounding mercury-Wells overfilled so as to assume a mercury-surface above the baseplate, a card or face supported by the pivot, a lever jointed to the card or face, and contact-pieces carried by the lever to engage the central mercury-Well and surrounding mercury-surfaces, substantially as specified.

4. In a contact arrangement on ships compasses for electrically transferring the respective positions of the needle, the combination of a base-plate having a central mercury-Well, a pivot centrally located in the Well, a series of surrounding mercury-Wells overfilled so as to assume a mercury-surface above the baseplate, a card or face supported by the pivot, a lever jointed to the card or face, and contact-pieces carried by the lever to engage the central mercury-Well and surrounding mercury-surfaces, and a counterbalance for the lever, substantially as specified.

In testimony that I claim the foregoing as my invention I have signed my name, in presence of tho subscribing Witnesses, this 6th day of January, 1903.

BERNHARD FREESE.

Witnesses:

F. A. BRYCE, Gr. HOGERMANN. 

